Patent attributes
An apparatus for processing substrates using a multi-chamber processing system (e.g., a cluster tool) that has an increased system throughput, increased system reliability, a smaller system footprint, and a more repeatable wafer history. Embodiments provide for a cluster tool comprising first and second processing racks, each having two or more vertically stacked substrate processing chambers, a first robot assembly able to access the first processing rack from a first side, a second robot assembly able to access the first processing rack from a second side and the second processing rack from a first side, a third robot assembly able to access the second processing rack from a second side, and a fourth robot assembly able to access the first and second processing racks and to load substrates in a cassette.